fixes #2407 - Add STI to settings model

Also adds some tests for rendering new/missing STI models, and
refactors the old default_settings loader into the new sub-models.
fixes #2430 - undefined method gettext_translation_for_attribute_name
Added rails and dependencies to comp
fixes #2428 - a workaround for an issue with SETTINGS[:libvirt] not being properly initialized in rpm environments
moved files to /app/services
moved /lib and /models files to app/models/concerns
move to controller/concerns
modified audit_extensions
modified host_common
modified orchestration
modified report_common
modified taxonomix
modified authorization
modified fog extensions model
modified fog extensions aws
modified fog extensions libvirt
modified fog extensions openstack
modified fog_extensions ovirt
modified fog extensions vsphere
modified foreman sti